Sheet metal forming equipment



April 1943- c. s. KASPER SHEET METAL FORMING EQUIPMENT Filed Feb. 23, 1940 ATTORNEY.

c055 smns 8 55;

Patented Apr. 20, 1943 UNITED STATES PATENT and Midland Steel Products Company,

Cleveland,

Ohio, a corporation of Ohio Application February 23, 1940, Serial No. 320,349

12 Claims.

This invention relates to new and useful improvements in sheet metal forming equipment and more particularly to the provision of means for automatically inserting a pair of mandrels into a die formation for processing a tube, and for retracting the mandrels from the formed tube, and relates more particularly to adapting a mechanically operated device of this character to the usual punch press.

Another important object of the invention is to provide means by which the mandrels are fully inserted and are at rest during the final stage or bottoming of the dies to form the tube into round cross section.

Another object of the invention is to provide simple form of ejecting mechanism to loosen or free the formed tube from its die by use of the mandrels prior to the completion of their retraction from the work.

A further object of the invention is to provide a simple and inexpensive mechanism of the foregoing characteristics which can be readily applied to the usual punch press.

Other objects and advantages of the invention will become apparent during the course of the following description.

In the accompanying drawing forming a part of the application and wherein like numerals are employed to designate like parts throughout the several views.

Fig. l is an enlarged perspective view of tube formed by the apparatus.

Fig. 2 is a perspective 'view of a punch press with the apparatus associated therewith,

Fig. 3 is a top plan on :an enlarged scale of the bed of .the press with the automatic mandrel applied thereto,

Fig. 4 is a side elevation of the same,

Fig. 5 is an enlarged view of one end of Fig. 4 with parts thereoi shown in section to clarify the construction.

Referring more in detail to the drawing, the numeral idesignates a piece of laced tubing formed with the herein described apparatus. It will be observed that the two longitudinal edges of the blank or stamping forming the tube are provided adjacent opposite ends with complementary interlocking dove-tailed recesses 2 and tongues 3 to prevent separation of the longitudinal edges after formation of the tube. complementary interlocking tongues and grooves have a very snug fit with each other, which is facilitated by cutting the stamping and interlocking tongues 3 with the innermost of the tube. Thus, the burr side of the These burr side of the edge the tongues, represented by the lower half of the thickness of the tongues is slightly smaller than the other half of the thickness of the tongue edge, or in other words has a slightly tapered edge so that the tongues snugly wedge into their corresponding recesses 2, and can be brought down' flush therewith, in firm interlocked relation to provide a smooth periphery for the tube under the power of the dies.

The numeral 4 designates the usual punch press having a bed 5 and reciprocatory ram with its customary slide carried through one complete cycle of reciprocation each time the treadle 8 is depressed to operate the usual clutch associated with the drive.-

The slide 1 of the press is provided with an upper die shoe 9 which is secured thereto transversely thereof and extends laterally thereof for substantial distances on either side of the press as clearly shown in Fig. 2. An upper die In is secured to the shoe 9 by the usual means. The bed 5 of the press is provided with the usual bolster blocks ll upon which is secured a lower die 12, complementary to the upper die It). For forming a tube section, the upper and lower dies are each provided with a longitudinally extending arcuate groove, the walls of which form the tube into its finished contour. It will of course be understood that four operations are performed upon the blank from which the tube is made prior to its final forming in the apparatus herein disclosed. 3 Mounted to be projected and retracted from opposite sides of the press, into and out of the work between the two dies, during press operations are a pair of longitudinally aligned mandrels l3, the same size as the interior of the tube to be formed. As the mandrels and their operating mechanisms are identical, a description of one will suiiice for both. The free end of each mandrel passes through a transverse opening in an ejector block I4 which is vertically reciprocal against the end of the lower stationary die block 12. This ejector block is normally urged upwardly by a coil spring seated in a recess in the bolster block H, and bearing against the under face of the block so as to normally bias the block upwardly upon a pair of vertical guide pins l6 screwed into the bolster block as best appreciated from Fig. 5. The ejector block is urged upwardly against the underside of its respective mandrel 13 to cause it to move vertically to a limited degree to loosen the formed tube from the lower die. This slight vertical movement of the mandrel is permissible due to its inner'end being provided with a T-shaped fitting I! having the stem thereof provided with a vertical slot l8 through which a pin l 9 projects for fastening the stem in the bifurcated end of a rack bar 20 disposed in alignment with its mandrel.

A support 2| is secured to the press bed at each side thereof to project a substantial distance laterally thereof as illustrated, to support a gear box 22 at its outer end. The rack bar slides through this gear box in mesh with a large pinion 23 which feeds the mandrel into and out of the dies and tube. The pinion 23 is keyed to a shaft 24 upon which is also keyed a smaller pinion 25. Pinion 25 meshes with a vertically movable tubular rack 26 which is provided with an internal shoulder 21 by a counterbore. Slidably mounted in the bore of the tubular rack26 is a stout rod 28 having an enlarged lower end 29 for abutment with the shoulder 21 to move the rack upwardly and thereby move the rack bar 20 to the right of Fig. 5 for retracting its connected mandrel from the dies and tube.

The upper end of the rod 28 is threaded as at 30 to be adjustably mounted in the outer end of the upper die shoe 9 so that the rod 28 partakes of the same movement as the ram or slide of the press. Of course, it will be appreciated that this mandrel operating mechanism is duplicated at eachside of the press so that the two mandrels are simultaneously operated. Mounted upon each rod 28 is an adjustable spacer collar 3| having a-reduced portion 32 to abut the upper end of a stout compression spring 33 positioned in the tubular rack 26 and having its lower'end engaging the shoulder 27. These compression springs 33 are preloaded so that they transmit the thrust from the die shoe 9 to the tubular rack 26 in order'to cause the rack bars 20 to move the mandrels I3 completely into the'work piece andbetween'the dies, prior to the bottoming of and final forming by these dies. After the mandrels l 3 have been inserted into the work pieceancl have come to rest, continued downward movement of the upper die shoe causes the upper die to bottom 'on the lower die and thereby form the article into complete tubular shape to cause an interlocking of the dove-tailed tongu'esand recesses.

Upon upward movement of the slide 7, the die shoel9 is carried upwardly along with the upper die Ill, during which time the ejector blocks I 4 move upwardly under the influence of their springs IE to move the mandrels vertically to a slight'degree and thereby loosen the work piece in the lower 'die. Upon continued elevation of the .slide,'the enlargedportions of the rods 28 willabutlthe shoulders 21 and move the tubular racks 26 vertically. to cause counter-clockwise movement of the pinions 23 and 25 thereby mov-' ing rack .bars 20 outwardly in opposite directions to completely withdraw the mandrels I 3 from the lower die l2 to facilitate withdrawal of the formed work piece and the admission of another.

It will of course be'understood thatvarious gear ratios maybe provided in the gear box 22 and thattwo or more rack bars 20 may be associated with each support for simultaneously operating two pairs of mandrels in the event that each die is provided with a pair of grooves to receiveand form a pair of tubes, simultaneously. It will also be understood that various changes in the shape, relation and sequence of operation may" be changed without departing from the spirit of theinvention or the scope of the appended claims, I

I claim:

1. A sheet metal former comprising a press having a slide and a bed having complementary dies, one on the slide and the other on the bed, a pair of aligned, opposed reciprocatory mandrels mounted on opposite ends of the bed, and means connected with the slide for moving said mandrels in unison in opposite directions to project them into the work upon descent of the slide, said means being yieldable after predetermined movement of the mandrels whereby said mandrels remain stationary during bottoming of the dies.

. 2. A sheet metal former comprising a press having a slide and a bed having complementary dies, one on the slide and the other on the bed, a pair of opposed aligned reciprocatory mandrels mounted at opposite ends of the bed die and having rack bars, a pinion train meshing with each bar for compelling itin opposite directions, a hollow rack also meshing with said pinion train and having a shoulder, a rodsecured to the slide and having a head slidable in said hol-' low rack, and a loaded spring received in said hollow rack against said shoulder to drive said mandrel to final position in the work prior to bottoming of the dies. 1

3. A sheet metal former comprising a press having a slide and a bed provided with complementary dies, one for the slide and the other for the bed,a pair of aligned, opposed mandrels mounted at opposite ends of the bed die and being lengthwise reciprocable, said mandrels having rack bars extending outwardly at the sides of the bed, and said slide having a pair of racks spaced laterally thereof, and pinions meshing with said rack bars for simultaneously moving said mandrels. I

4. A combination with a pair of relatively movable dies, of a retractable reciprocatory mandrel adapted to be movedin and out between said dies, a rectilinearly movable member for moving said mandrel, said mandrel being connected to said member to be independently moved transversely thereof during bottoming of said dies, and compression spring means engag ing said mandrel to normally hold it aligned with said member and being yieldable during bottoming of the'dies to store power to move the mandrel and loosen the work between the dies upon separation thereof.

5. A sheet metal former'comprising a press having a slide and a bed provided with complementary dies, one on the slide and the other on the bed, a reciprocatory mandrel adapted to move between saiddies, means for moving said mandrel in a rectilinear path, and said mandrel being connected with said last named means to enable it to be movable nor'malthereto and independently thereof.

6. A sheet metal former comprising a press having a slide and a bed provided with complementary dies, one on the slide and the other on the bed, a reciprocatory mandrel adapted to move between said dies, means for moving said mandrel in a rectilinear path, and said mandrel being connected with said last named means with a pin and slot connection to be movable independently thereof, and means engaging said mandrel to move it relative to said means when the slide elevates one of said dies. 7

7. A sheet metal former comprising a press having a slide and a bed provided with complementary dies, one on the slide and the other on:

the bed. a r iprocatory mandrel adapted to move between said dies, a rectilinearly movable member axially aligned with said mandrel for moving the same, and a pin and slot connection between said member and mandrel whereby said mandrel can be moved relative to said member.

8. A sheet metal former comprising a press having a slide and a bed provided with complementary dies, one on the slide and the other on the bed, a reciprocatory mandrel adapted to move between said dies, a rectilinearly movable member axially aligned with said mandrel for moving the same, and a pin and slot connection between said member and mandrel whereby said mandrel can be moved relative to said member, and spring means engaging said mandrel and compressed by the dies coming together to store power to elevate the mandrel independently of said member upon separation of said dies.

9. A sheet metal former comprising a press having a slide and a bed having complementary dies with tube forming recesses to form a tube therebetween, and pair of mandrels at opposite ends of said dies, means operatively connecting the mandrels with said slide for projecting said mandrels into opposite ends of said tube upon descent of the slide, and for withdrawing said mandrels from opposite ends of the tube upon ascent of said slide.

10. A sheet metal former comprising a press having a slide and a bed provided with complementary dies, a reciprocatory mandrel to move between said dies, a rack bar for moving said mandrel, a rack sleeve vertically movable in said bed and having a shoulder intermediate the ends thereof, a member secured to said slide and operating in said sleeve, said member having a head to abut said shoulder during the upstroke of said slide, a compression spring in said rack engaged by said member to move the rack downwardly during downstroke of the slide, and a pair of pinions forming a driving connection between said rack sleeve and said rack bar.

11. A sheet metal former comprising a press having a slide and a bed with complementary dies, one on the slide and the other on the bed, a reciprocatory mandrel movable between said dies, means operatively connecting said mandrel and slide for moving said mandrel in opposite axial directions into and out of the work between the dies, and a pre-loaded spring mounted between said slide and said means to operate the latter and yieldingly drive said mandrel to a position into the work, said spring yielding upon predetermined load to cause the mandrel to stop its inward movement prior to bottoming of said dies.

12. A sheet metal former comprising a press having a slide and a bed having complementary dies, one on the slide and the other on the bed, a pair of aligned opposed reciprocatory mandrels mounted on opposite ends of the bed die, rack and pinions means operatively connected to said slide for moving said mandrels in unison in opposite directions to project them into the work upon descent of the slide, and spring means interposed in said rack and pinion means and adapted to yield when the mandrels are projected to their innermost positions whereby the mandrels remain stationary during final downward movement of the slide die.

CASS S. KASPER. 

